Foam cushions and seating structures



y 6, 1965 w. P. BAERMANN 3,193,328

FOAM CUSHIONS AND SEATING STRUCTURES Filed June 10, 1965 3 Sheets-Sheet1 INVENTOR: WALTER F? BAERMANN ATT'YS July 6, 1965 w. P. BAERMANN FOAMCUSHIONS AND SEATING STRUCTURES Filed June 10, 1963 3 Sheets-Sheet 2 m ill A L FIG? f INVENTOR.

y 1965 w. P. BAERMANN 3,193,328

FOAM CUSHIONS AND SEATING STRUCTURES Filed June 10, 1963 3 Sheets-Sheet5 INVENTOR.

WALTER F? BAERMANN United States Patent Ofiice aisasas Patented July 6,1955 3,1?3328 FUAM CUSHEGNS ANT) EiEA'lilNG STRUKITURES Walter P.Baermann, Waynesville, NAIL, assignor to Prestige Furniture Corporation,Newton, N.C., a corporation of North fiarolina Filed June 10, B63, Ser.No. 286,549 1 Claims. (Cl. 297-456) This invention, in general, relates.to articles of furniture and to cushions useful therewith and moreparticularly pertains to foam cushions, especially seat and/or back restfoam cushions for seats, chairs, sofas and the like, the upper side orface of which cushions depress in approximate conformity to the humananthrcpologic curve when a human is seated thereon.

Research on seating and its relationship to human anatomy has resultedin better understanding of the requirements which a seating piece shouldmeet in order to fulfill its proper function. From the consideration ofsuch factors as seat height, depth, pitch and contour, as well as lowerback, shoulder, and neck support, a series of anthropologic curves havebeen established which provide proper body support and posture controlor, in general, eliminate those fatigue producing factors whichultimately cause seating discomfort.

However, it is not alway aesthetically desirable that the seat and backsurface contours follow these anthropologic curves, and in cases wherereversible cushions are desired, surface contouring would be impossiblebecause of the necessity for cushion symmetry.

This invention achieves proper anthropologic seating in upholsteredfurniture pieces without the necessity of contouring seat and backsurfaces. Essentially this system proposes a cavity, or cavities, withinthe cushioning material, contoured in such a manner that when the weightof a seated individual is placed on it, the resultant compressed cushioncontours are those desired. The contours of these cavities or coresdepend upon the shape, position, and material density of the cushioningmaterial in the particular seating piece, as well as the method andmaterials used in supporting the cushions.

Seats, chairs, sofas and the like, cushioned and uncushioned, have beencontoured so that the upper surface of theseat and front surface of backsupport follow the approximate anthropological curve in order to providea comfortable low fatigue support for a human seated thereon. Theseanthropologically curved seats on articles of furniture, however, havepractical disadvantages and are not aesthetically appealing to manypersons.

The seating surfaces of foam cushions of this invention, which arenonanthrcpologically curved, have a normal shape such as convex, fiat,or even slightly concave, etc. V-hcn a person is seated thereon in thenormal seating position, however, the supporting surfaces of thecushions depress unevenly to form substantially an anthropologic curvesupport. The anthropologic curve-producing structures of the foamcushions of the invention may be so situated in the cushion that theyprovide the anthropologic curve support when either face of the cushionis up.

The out -ropologic curve is the curved line A-A shown in the side viewsof the drawings. Starting with the front edge of a seat (correspondingapproximately to the knees of a seated person) it may arch upwardly fora short distance and then assumes a longer, concave, relatively deepreverse bend turning upwardly at the rear portion of the seat. Theanthropologic curve continues its concave curvature relatively sharplyinto the lower part of the back support member wherein it assumesanother reverse bend of convex shape in the lower portion of the backrest member. The curve may again reverse at about the midback supportarea of the back rest and continue through the remainder of the backrest in a slightly concave (or straight) path.

Briefly, the foamed elastorner cushions herein contemplated comprisefoamed elastomer, three dimensional bodies such as foamed polyurethanebodies wherein the cushion is provided wit-h a hollow core or cavity,the wall or walls of the cavity defining a collapsible pocket or pocketsin the foamed elastomer. In preferred embodiments of the invention, thecavities are substantially symmetrical at least in vertical section andare located approximately equidistant from the upper and lower sides ofthe cushion. Such structure allows the'cushion to be used with eitherside facing up, either side of which yields under the weight :of aperson resting thereon to provide the anthropologic curve support. Thecavities may be tapered in both dir ctions from their widest pointtoward opposite edges of the cushions.

The generic principles of the invention, and practical applicationsthereof, will be further explained with regard to several preferredembodiments of the invention which are illustrated in the drawingswherein:

FIG. 1 is a side elevation of an embodiment of the invention, i.e.,center-cored, reversible seat and back support cushions, on an articleof furniture with the cushions in the relaxed, normal state;

PEG. 2 is a side elevation of the embodiment of FIG. 1 with thesupporting surfaces of the cushions depressed into the anthropologiccurve support surface, as would occur when a person is seated in normalposition on the article of furniture;

FIGS. 3 and 4 are, respectively, a top plan view and a section onsection 4-4 of FIG. 3 of an embodiment of a center-cored cushion of theinvention;

FIGS. 5 and 6 are, respectively, a top plan view and a section onsection 66 of FIG. 5 of another embodiment of a center-cored cushion,While FIGS. 7 and 8 are similar views, the latter taken on section SS ofFIG. 7, of still another embodiment of a center-cored cushion embodiedby the invention;

FIGS. 9 and 10 are, respectively, side elevations of another cushionembodiment, i.e., a bottom cored cushion, on an article of furniturewith the cushions in the relaxed, normal state and in a depressed stateas would occur when a person is seated normally on the article offurniture.

Referring to the drawings, there is shown in FIGS. 1 and 2 a chair 1comprising a seat frame of any desired construction, on which seat frameare mounted chair legs 3. The seat frame 2 and legs 3 are shown asmerely illustrative of one style of seat frame and leg structure. Theseat frame may be deeper as in overstuffed chairs, sofas, Sectionals,etc., and may have one or more arm rests of any desired construction.The cushion supporting means of the seat frame may be a nonyieldingtype, e.g.,

a rigid, solid web, board, etc. or an open, slat-type support, or it maybe a resilient type such as a coil spring support, a spring supported,open, wire network support, foam clastomer block support, etc. The backsupport frame 4, may be attached to the seat frame in any suitablemanner and may have any of the aforementioned types of construction,i.e., the nonyielding or rigid types or the resilient types.

A seat cushion 5 (or a series of side-by-side seat cushions) lie on theseat frame 2. The seat cushion 5 is of the reversible type and hencewill most advantageously be unattached or detachably connected to theseat frame and/or back frame. It may, however, be used on furniture oftight-seat construction, i.e., furniture with the seat cushion orcushions attached to a frame supported on the seat frame or to the seatframe itself so as to be nonreversible in the sense that the cushion orcushions are not readily removed and turned over to face the other sideupward.

The seat cushion comprises a foam elastomer body portion 6 which has acavity 7 in the rearward portion of the cushion. The lower and upperwalls 8, 9 of cavity 7 define the double taper air cavity or pocket 7 inthe cellular, foam elastomer cushion. For a reversible cushion, thehorizonal mid-plane of the cavity 7 should be about midway between theouter, weight supporting surfaces 16, 11 of the cushion. The curvedwalls 8, 9 of cavity 7 are curved substantially symmetrically withreference to said horizontal mid-plane.

When a person is seated on cushion 5, the upper surface 19 of thecushion is depressed unevenly under the persons weight whereby the uppersurface assumes a curvature of the anthropologic curve type in the seatcushion. The cavity 7 collapses under weight of the seated personandexpands to normal size upon removal of weight.

The dimensions of the cavity 7 and its location relative to the rearedge 12 and front edge 13 of the cushion, as well as the particularcurvature and double taper of walls 8 and 9, dependupon the thickness ofthe cushion 5, normal shape of the weight supporting surfaces or majorwalls 10, 11, e.g., fiat, convex, etc., position of the cushion 5relative to the back supporting cushion 16 and density of the foamedelastomer as it relates to amount of give under given compression orweight conditions, as well as upon method and materials used to supportthe cushion 5, e.g., rigid vs. resilient support frame structure andcharacter of the latter. As a general rule, however, the front edge ofcavity 7 is located nearer front edge 13 than to rear edge 12 of cushion5; the rear edge 14 of cavity 7 is near, or may even intercept in somecases, the rear edge 12 of cushion 5; the taper and curvature of upperand lower walls 8, 9 is substantially symmetric with reference to thehorizontal mid-plane of cushion 5 fora cushion capable of providingsubstantially the same anthropologic curve support regardless of whethersurface lil'or surface 11 is facing upwardly; and the point of greatestdivergence of walls 8, 9 of cavity 7 is nearer the rear edge 12 than tothe front edge 13 of cushion in order to allow surface It (or surface 11when the cushion 5 is turned over) to collapse to the greatest degree atthe point of lowest curvature of the anthropologic curve 'AA,whicl1point is closer to rear edge 12 than to front edge 13.

The function of cavity 7 is that of varying the wall thickness of thefoamed elastomer cushion 5 and hence varying the depth of depression ofthe major Wall or upper surface 10 (or surface 11 when the cushion isturned over) under the weight of a person sitting thereon. The wallportion 17 between the upper surface 10 and upper wall 9 of cavity 7will collapse under weight comparatively easily as compared with thecollapsibility of the frontal portions of the cushion wherein the foamelastomer is continuous over the entire thickness of the cushion. As airin the cavity 7 escapes to the atmos phere, the cavity 7 collapseseasily until upper wall9 contacts lower wall 8 of the cavity. Uponcomplete or substantially complete collapse of cavity 7 (FIG. 2), theupper and lower walls 8, 9 are in contact and the wall portions 17 and18 (the latter lying between cushion surface 11 and cavity wall 8) coactto resist further easy depression of surface 10. At this stage,contacting wall portions 17, 18 behave as if they were a singlethickness of foam elastomer and further compression thereof undera'persons weight is governed by the inherent compressibility of theparticular foam elastomer.

The ultimate curvature of the surface 10 of seat cushion 5, under theweight of a person seated normally thereon were turned over.

The cavity 7 may extend between and intercept op- 4 posite side edges ofthe cushion 5, i.e., a cavity open at both ends. It may have, on theotherhand, one or more narrow, divider walls of foam elastomer extendingthereacross in a direction from front to rear so as to divide the cavity7 into two ormore side-by-side compartments and/or to close off the endsof the cavity 7. The foam elastomer divider walls may be interlinked bylaterally extending, foam elastomer walls which together divide cavity 7into a series of rows of side-by-side compartments. These variations of'the invention are further discussed with reference to FIGS. 3-8, infra.

A convenient method for manufacture of foam elastomer cushions 5, withor without said foam elastomer divider walls and/or cross walls, is tomold the expandable elastomer composition, which includes the blowingagent which foams the elastomer compositions into cellular, elastomerform, in a'blowing mold in the form of upper and lower half sections 19,20, which half sections may have the same shape and dimensions and hencemay be blown into foam elastomer half sections in the same or anidentical blowing mold. The mold is shaped to provide the wall 8 or wall9 of the blown, molded half section. When the two half sections arejoined together as shown, the cavity 7 is formed by walls 3, Q. When oneor both ends of the cavity 7 are open, whole cushion 5 may be blown in asingle mold in which is mounted a mold core shaped like cavity 7. Aftermolding, the outer forms of the mold may be retracted, and the moldedcushion may be drawn sideways off the mold core. In another type ofmolding technique, the mold core is detachably mounted on the mold, isdetached and removed from the mold with the molded cushion, and is thenremoved therefrom and remounted in the mold for the next moldingoperation.

The foam elastomer, back support cushion 16 is similar in structure toseat cushion 5. It has a double taper cavity 21 of similar, though notnecessarily identical, shape, location, and dimensions to cavity 7. Itmay also be made from two half sections 22, 23 bonded together like thesections of cushion 5 or as a unitary molding.

The front, lower corner 24 of foam elastomer cushion 16 ordinarily willyield a sufficient amount to allow the lower edge of the back supportingsurface 25 to depress sufliciently to assure an approximately smoothcontinuation from the upper surface 10 of cushion 5 of the anthropologiccurve A-A onto the surface 25 of cushion 16. The surface 26 of cushion16 just above the lower edge should be co'nvexly arched when a personslower back is resting thereagainst to provide a support areacorresponding to the lower back curvature. This convex arch isrelatively sharp. The convex or arched surface segment 25 results fromthe relatively greater resistance to compression of the unbroken foamedelastomer body portion behind the arched surface 26 as compared with themore easily distorted lower corner 24 and the body of the foamedelastomer in the area of the lower portion of cavity 21. The cavity 21,when fully or substantially fully collapsed with cavity wall 27 pressedagainst cavity wall 28, causes the upper portions of surface 25 toassume a substantially straight or slight concave configurationcorresponding to the upper portions of the anthropologic curve A-A (FIG.2).

The variables such as foam density, type of cushion support, etc.,enumerated supra with regard to cushion 5, should also be considered indetermining the specifications for the back cushion 16 and its cavity 21to obtain the optimum anthropologic curve for surface 25 of cushion 16.Cushion 16, like cushion 5, because of the symmetry of walls 27, 28 :ofcavity 21 relative to the mid-plane thereof, is reversible without lossof theanthropologic support qualities of the cushion.

Several embodiments of cavities with previously discussed foam elastomerwall divider walls and cross walls are shown in FIGS. 38 for'seatcushion 5. Though not illustrated, these walls may also be used in thecavity 21 of back rest cushion 16. Referring first to FIGS. 3 and 4, theends of cavity 7 are closed by foam elastomer walls 30, 31. The cavity 7is further subdivided into four, side-by-side compartments or pockets 7by the foam elastomer divider walls 32, 33, 34 extending from front edge13 to rear edge 1 of cavity '7 and also from lower wall 8 to upper wall9 of cavity '7. The walls 3b, 31, 32, 33, 34 are sufiiciently narrow sothat they are flexible enough to readily collapse, partly by compressingand partly by bending, under weight. They have, however, tsufiicientrecovery, resiliency or strength so that they tend to return to theirnormal, straight wall form when the weight is removed. The primaryfunction of walls 31-34 is to provide collapsible, resilient supportmembers f r the wall portions 17, 13 so that they retain their normalshape and do not sag under their own weight.

In the embodiment of FIGS. 5 and 6, the cavity 7 is subdivided into agreater number of smaller pockets 7 by cavity end walls 36, 37, front torear divider walls 38, 39, 41 and intersecting cross walls 41, 42, allbeing narrow walls of foam elastomer and of the character of walls36-34. The walls 36-41 and Walls 41, 42 may be joined together at theirrespective junctures 43, or, if greater flexibility of c-ollapsibilityof the cavity at these junctures is desired, the walls 36-42 may besplit at the junctures whereby each segment of walls 36-40 (or onlywalls 38- and/ or walls 4-1, 42, is not joined to an intersecting wallsegment, whereby each wall segment is collapsible independently of anintersecting wall segmentthereby eliminating the less flexible and more'difficultly collapsible junctures 43.

The embodiment of FIGS. 7 and 8 is similar to that of FIGS. 5 and 6 andlike numerals have been used to designate like parts. The essentialdifference is that the embodiment of FIGS. 7 and 8 has two morecross-walls ea, 45, dividing cavity 7 into even more compartments orpockets 7". The spacings between walls 41-45 are considerably lesstoward the rearward edge 12 of the cushion in order to impart greatercloser support members toward the rearward end of cavity 7, where thegreater portion of the weight of a seated person is concentrated. As 1nFIGS. 5 and 6, the walls may be split to avoid the wall junctures. Inthe embodiments of FIGS. 5-8, the crosswalls 41-45 may be the onlyflexible walls employed as support walls, if desired; the divider walls32-35 may be omitted in such case.

The foam elastomer walls 31-45 may be molded integrally with only onecushion half section 1% or 20 and may, upon assembly of the halfsections, have their free edge bearing freely and unattached to thecavity wall of the other half section. As an alternative, the freeedgees of walls 31-45 may be bonded to the said cavity wall of theopposite half section when the sections are assembled to form cushion 5.As still another alternative, the walls 3145 may be molded as half Wallson the cavity walls 8, 9 of sections 19, 20 and the free edges of t-hehalf walls may be bonded together when the sections are assembled.

Many foam elastomers have sufiicient gas permeability so that air canescape readily from cavity '7 when it 18 closed by end walls or from thecavity pockets or compartments 7" when they are collapsed under weightand so that air can be drawn readily into the cavity 7 or pockets 7 or7" when the wall portion 17 or 18 springs back to normal position uponremoval of the weight there-on. In the event the particular foamelastomer employed, however, has a relatively low gas permeability, theescape and return rate for the air can be augmented by providing airvent holes in wall portions 13, 19 or end walls 31, 32 or 36, 37 to ventthe cavity 7 or individual pockets 7 or 7" to the atmosphere. Thepockets 7 and 7 may also be intercommunicated by air vent holes throughthe Wall portions therebetween.

The cushion structure of the embodiment of FIGS. 9 and 10 is somewhatdifferent from that previously de scribed. There is illustrated in FIGS.9 and 10 an article of seating furniture like that of FIGS. 1 and 2. Theseat cushion 5t and the back support cushion 51 are of the nonreversibletype in the sense that the anthropologic curve support character of thecushions is realized from only one side of the cushions. The embodimentof FIGS. 9 and 10, therefore, may be used primarily on seatingstructures where nonreversible cushions are called for in the seatingstructure design. In FIGS. 9 and 10, the cushions Sit and 51 each have atransverse cavity 52, 53 in the surface 54, 55 lying against the seatframe 2 and back support frame structure 4 supporting each respectivecushion. Cavity 52 is defined by a transverse, arched wall 56 archingfrom the lower, rearward edge 57 of cushion 5!] toward the frontalportion of the cushion. Its forward edge 58 is closer to the front edge59 than to the rear edge of cushion St The highest point 60 of archedwall as corresponds substantially with the deepest dip in the seatportion of the anthropologic curve A-A.

The cushion Si in its normal, relaxed state rests on the cushion supportstructure of seat frame 2 at its rear edge and the frontal undersurface61, the upper surface 62 of cushion 5%) being flat, slightly convex orother nonanthropologically curved shape, as desired. When a person isseated on cushion 50 with his back resting against cushion 51, thecushion portion above cavity 52 collapses readily until the cavity wall56 contacts the seat cushion support structure on seat frame 2. Themaximum collapse occu'r-s substantially at the highest arch point 6%with progressively lesser degrees of collapse on either side thereof,the relative amounts being a function of the shape of arched wall 56.The ultimate result is that the arched wall 56 of cavity 52substantially completely collapses and the cushion assumes the shapeshown in FIG. 10 wherein the upper surface has a curvature correspondingto the seat portion curvature of anthropological curve AA.

The cavity 5-3 of back rest cushion 51 behaves in a similar fashion whena person rests his back thereagainst. Its arched wall es collapsesagainst the cushion support structure of the back rest frame member 4 sothat the surface 64 assumes a curvature corresponding with the upper andlowerback portions of the anthropologic curve. The cavities 52 and/or 53may have front to rear foam elastomer divider walls and/or transversewalls of like chracter to the walls of FIGS. 3-8 to add resilientintermediate or end support members to the cushion wall portion betweencavity wall 56 and upper wall 62.

It will be appreciated that the generic principles of the the inventionwith reference to articles of seating furniture or other seatingarticles and with reference to foam elastomer cushions therefor can bepracticed i-n a wide variety of embodiments, the specific embodimentsillustrated and described being merely illustrativeof practicalapplications of these principles.

The anthropologic curve support for seated persons can be realized bythe application of the principles of the invention in seating structuressuch as cushioned chairs, sofas, etc., with straight backs, slopingbacks, transversely rounded backs, low backs, or high backs. The seatingstructures may even be backless, in which case only the seating cushionportion of the invention applies, as it may also in seating structureswith back cushions constructed other than as herein described. Withminor modifications due to a difference in weight-support distributionand nature of the anthropologi-c curve, the cavity-type cushions of theinvention may also be used 111 reclining, lounge seats and the like. Itwill be further understood that the foam elastomer cushionbodiesusually, though not necessarily, will be covered with a flexiblecovering, e.g., fabric, leather, plastic film, etc,

The invent-ion is hereby claimed as follows:

1. A seat comprising a seat supporting member with a foam elastomercushion supported thereon, said cushions upper, weight supportingsurface being of a shape other than an .anthropologically curved shapewhen the cushion lbody.

is in the relaxed state, said cushion further having einbodied in thefoam elastomer body thereof a transversely extending cavity defined byat least one arched wall having its highest point of arch substantiallyopposite the lowest dip of the corresponding portion of theanthropologica'l curve of a person seated in the normal seating positionon said seat, said arched wall collapsing when said person is seated insaid normal seating position.

2. A seat as claimed in claim 1 wherein said cushion is reversible andhas substantially flat to convex, opposite,

weight supporting surfaces, and said cavity is about midway between saidsurfaces and is defined by substantially symmetric, oppositely disposed,transverse, oppositely arched walls formed of said foam elastomercushion 3. A seat as claimed in claim 1 wherein said cushion has asubstantially flat to convex upper, weight supporting surface, theopposite surface of said foam elastomer cushion body having therein asingle transversely extending cavity recess in said opposite surfacedefined by an arched wall, said cushion 'in the relaxed state beingsupported on said supporting member with said arched, cavity wallunsupported.

4. A seat comprising a seat supporting member with a foam elastomercushion supported thereon, said cushions upper, weight supportingsurface being of a shape other than an 'anthropologically curved shapewhen the cushion is in the relaxed state, said cushion further havingembodied in the foam elastomer body thereof a transversely extendingcavity defined by at least one arched wall having its highest point ofarch substantially opposite the lowest dip of the corresponding portionof the anthropological curve of a person seated in the normal seatingposition on said seat, said arched wall collapsing when said person isseated in said normal seating position, an upwardly extending, backcushion supporting member with a foam elastom'er back cushion with itsback surface resting thereagainst, said back cushioris front surfacebeing of -a shape other than an anthropologically curved shape whensaidback cushion is in the relaxed state, said cushion further havingembodied in the foam elast-omer body thereof a transversely extendingcavity defined by at least one arched wall having its highest point ofarch substantially opposite the lowest dip of the corresponding portionofthe anthropological curveof a person seated in the normal seatingposition on said seat, said arched wall collapsing when said person isseated in said normal seating position.

'5. A seat as claimed in claim 4 wherein each of said cushions isreversible and has substantially fiat to convex, opposite, weightsupporting surfaces, and said cavity is about midway between saidsurfaces and is defined by substantially symmetric, oppositely disposed,transverse,

8 oppositely arched walls formed'of said foam elastomer cushion body.

6. A seat as claimed in claim 4 wherein each of said cushions has asubstantially flat to convex outer, weight supporting surface, theoppositezsurface of said foam 'elastom-er cushion body having therein asingle, trans- Iversely extending cavity recess in said oppositeysurfacedefined by an arched wall, said cushion in the relaxed state beingsupported on said supporting members with said arched, cavity wallunsupported.

'7. A' foam elastomer cushion body molded with a weight supporting,major wall having a shape other than an anthropologically curved shapewhen said cushion is in the relaxed state, a second major wall shapedand dimensioned similarly to said first-mentioned major wall and locatedon the side of said cushion opposite said firstmentioned major wall,whereby said cushion body is a reversible type, said foam elastomer bodyhaving therein a transversely extending cavity about midway between saidmajor walls and'defined by oppositely disposed, transverse, oppositelyarched walls of said foam elastomer cushion body, which arched walls aresubstantially sym metric with reference to the mid-plane between said'zmajor walls, one of said cavity substantially completely collapsingwhen a person is seated on a major wall in a position wherein the lowestdip in his anthropologic curve substantially opposite the point ofgreatest divergence of said arched walls. 8. A cushion body as claimedin claim 7 wherein said cavity contains at least one narrow wall of foamelastomer in said cavity extending from one arched wall of said cavityto the other arched wall thereof.

9. A cushion body as claimed in claim 7 wherein said cavity contains aplurality of narrow walls of foam elastomer extending from one archedwall of the cavity to the other arched wall thereof.

'10. A cushion body as claimed in clai1n9 wherein there is also at leastone, narrow wall of foam elastomer extending between said plurality ofwalls and extending from one arched wall of the cavity to the otherarched wall thereof. 7

References Cited by the Examiner UNITED STATES PATENTS B. SHERRY,Primary Examiner.

1. A SEAT COMPRISING A SEAT SUPPORTING MEMBER WITH A FOAM ELASTOMERCUSHION SUPPORTED THEREON, SAID CUSHION''S UPPER, WEIGHT SUPPORTINGSURFACE BEING OF A SHAPE OTHER THAN AN ANTHROPOLOGICALLY CURVED SHAPEDWHEN THE CUSHION IS IN THE RELAXED STATE, SAID CUSHION FURTHER HAVINGEMBODIED IN THE FOAM ELASTOMER BODY THEREOF A TRANSVERSELY EXTENDINGCAVITY DEFINED BY AT LEAST ONE ARCHED WALL HAVING ITS HIGHEST POINT OFARCH SUBSTANTIALLY OPPOSITE THE LOWEST DIP OF THE CORRESPONDING PORTIONOF THE ANTHROPOLOGICAL CURVE OF A PERSON SEATED IN THE NORMAL SEATINGPOSITION ON SAID SEAT, SAID ARCHED WALL COLLAPSING WHEN SAID PERSON ISSEATED IN SAID NORMAL SEATING POSITION.